utils: bdaddr: Fallback to bootconfig to read serialno

In boot image header v4 builds, androidboot.* bootargs are
part of bootconfig (/proc/bootconfig). So fall back to
parsing bootconfig file to lookup androidboot.serialno
bootarg, if it is not found in /proc/cmdline.

Change-Id: Ie28aed52c379bd02aa0d50d31bbbe0982ed9b5b4
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
diff --git a/shared/utils/bdaddr/bdaddr.rc b/shared/utils/bdaddr/bdaddr.rc
index d4f007d..65706db 100644
--- a/shared/utils/bdaddr/bdaddr.rc
+++ b/shared/utils/bdaddr/bdaddr.rc
@@ -19,6 +19,8 @@
     user root
     group system
     capabilities NET_ADMIN
+    disabled
+    oneshot
 
 on post-fs
     start set_bdaddr